Two-thread overedge sewing-machine.



G. NIEDERMAYR. TWO-THREAD OVEREDGE SEWING MACHINE.

' APPLIOATIOK FILED DEC. 28, 1904.

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ABILIOATION FILED D110. 28, 1904.

Patented Nov. 8, 1910.

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G. NIEDERMAYR.

TWO-THREAD OVEREDGE SEWING MACHINE.

APPLICATION FILED 1130.28, 1904.

974,910. I Patented N0v.8,1910.

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G. NIEDERMAYR. TWO-THREAD OVBREDGE SEWING MACHINE. APPLIOATION FILED D110. 28, 1904.

974,91 O. Patented Nov. 8, 1910.

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NIEDERMAYR, 0F HATTERSHEIM-IN-THE-TAUNUS, GERMANY, ASSIGNOR TO AARON VAIL ROWLEY, OF FBANKFORT-ON-TI-IE-MAIN, GERMANY.

TWO-THREAD OVEREDGE SEWING-MACHINE.

Specification of Letters Patent.

Patented Nov. 8, 1910.

Application filed December 28, 1904. Serial No. 238,642.

To all whom it may concern:

Be it known that I, GEORG NIEDERMAYR, engineer, residing at 1 I-Iofheimerstrasse, Hattersheim in the Taunus, German Empire, have invented certain 1 ew and useful Improvements in Two-Th ead Overedge Sewing-Machines, of which the following is a specification.

In over edge sewing machines with upper and under threads, as at present constructed,

the sewing frame, or the sewing machine proper, is stationary, and the fabric is moved forward by the feed motion, with which arrangement a cloth presser is necessary. In this old construction, the stitch or seam is produced by means of a needle carrying the upper thread, a reciprocating threaded looper carrying the lower thread, and a spreader situated above the cloth, the arrangement being such thata nose situated near the point of the threaded looper carries the loop of the upper thread to the upper side of the cloth, while the spreader applies the thread of the threaded looper over the place through which the needle passes. WVith sewing machines arranged in this manner, with cloth presser and feed motion, the fabric is very easily distorted, and in particular when working rapidly, creases are formed in the fabric, so that the speed of sewing has to be comparatively small. According to the present invention these disadvantages are obviated by so constructing the mechanism of the sewing machine, that in forming the over-edge stitch the loop of the upper thread remains below the cloth, so

that the known arrangement of sewing machines for other kmds of stitchlng can be utilized in which the cloth remains station-' ary and the sewing frame moves along the cloth and in which no cloth presser is required. The output of the sewing machine is, by this means, increased about four-fold that of the usual over-edge sewing machines,

A special arrangement of this sewing machine is rendered particularly applicable for knitted fabrics, by causing the upper thread before entering the eye of the needle, to pass through a clamping device which holds it during the time of forming the loop, as with knitted fabrics, the friction of the upper thread within the fabric is not suflicient for insuring a perfect loop formation.

I will describe my said invention with reference to the accompanying drawings, in whicl1- Figure 1 shows a side view of the sewing machine. Fig. 2 a front view, Fig. 3 a sectional plan on line AA of Fig. 1, while Figs. 4, 5, 6 and 7 show to an enlarged scale the mode of forming the stitches, Fig. 8 shows the stitching or seam produced; Fig. 9 is a side elevation, with parts in section, illustrating chiefly the mechanism for moving the sewing frame; and Fig. 10 is a plan of the parts shown in Fig. 9.

The fabric 1 to be sewn is so placed upon the cloth plate 2 provided with vertical teeth, that the two edges to be sewn together are situated under the needle 3 of the sewing machine frame. The latter is arranged to slide parallel to the cloth plate in a guide in the direction of the arrow, its motion being made quicker or slower according to the size of the stitches to be produced.

The longitudinal motion of the sewing frame is effected along a toothed rack 37, situated parallel to the cloth plate 2, a toothed pinion 36 on the sewing frame being engaged with the said rack and being driven by means of a worm wheel 35 connected thereto, with which is engaged the driving worm 3 carried by the sewing frame.

The rack 37 is secured to two cross bars 38 one of which is shown in Figs. 9 and 10, said bars being fastened to the frame or table 39, and being connected by rods 40, 4.1 which also serve as guides for the slide 34L forming part of the sewing frame. In suitable bearings upon this movable frame, are journaled grooved rollers 30, 32, 33, engaged by a belt or rope 31 which travels to turn the wheel 30 and through it the shaft 7 on which said wheel is rigidly secured. The belt also engages two wheels (not shown) which are journaled on the stationary frame 39, the run which is engaged by the wheels 30, 32, 33, being substantially straight and parallel to the rack 37, as shown, so that the may be stopped and brought back to its starting point, the worm wheel "35 is mounted loosely on the shaft 42 to which the pinion '36 is secured rigidly, and a coupling pin normally connects said shaft to rotate with the worm wheel 35. If, however, the pin 43 be lifted out of engagement with the worm wheel .35, the latter will. rotate with out.actuating, the shaft-.42, and the operator can then turn the shaft 42 by hand in the opposite direction to bringthe slide .34: and the, .parts carried thereby, back to their original position.

The needle 3 is carried by the needle bar 1, which is actuated by the elbow lever. 5, and connecting rod 6 from the driving shaft 7. The latter carries an eccentric S which by means of connecting rod 9, crank shaft lOand connecting, rod 11 .imparts a to-andfro motionto .a toothed sector 12, which in its turn imparts the requisite to-and-fro motion to. the threaded looper 13 bymeans- [of a toothed pinion connected thereto.

The spreaderlet, which is formed with a notch at its. free end, is pivotallyniounted on a vertical stud 15 and is actuated by means oflan elbow lever 16, engaged with a cam drum 17 on the driving shaft. In addition, there is provided a thread-clamp 18, which 'holds the upper thread passing through it, when its pin 19 isactuated by means of the bentlever20, mounted on a counter shaft 21, which receives -a rocking motion from the main shaft by .means of an arm or tappet 22 and levers 23 and 24. As the lever20 rocks, its wedge-shaped end portion will at certain times en age the righthand end of: the pin 19 and force it against the spring 18 so as to relieve the pressure of said spring on the thread.

,The upper thread passes from the thread reel through the tension disk 25, through the rod 26 fitted with a tension spring and through the thread clamp 18 into the eye of the needle 3, while the under thread passes from the reel over the rod 27 likewise fitted ,with a tension spring, and through the eyes :28 and 29 to the threaded looper 13. Each of the rods 26, 27, is slotted, as shown in Fig.

2, for the passage of the thread, and springs 26, 27 press-.upward against collars 26 27 sliding on the said rods. The thread is thus held under tension.

'=The threaded looper 13 is of a perfectly semi-circular form and is provided in the well-known manner with two eyes and a groovefor the reception of the under thread. The center of said semicircle does not, however coincide with the loopers (horizontal) .axis of oscillation, but the distance'from said axis to the looper increases toward the free end of the looper. Owing to this eccentric arrangement the looper exerts practically no the semicircle a nose13 which prevents the loop of the upper thread from sliding off.

The nose 13 is located near the pivot of said looper and owing to this fact and to the spiral form of said looper (in edge View) the said nose does not exert a pull on, or, in other words, does not stretch the needle loop as is the case in constructions where the nose is located near the point of the looper. The danger of breaking the thread and of crumpling or of detaching the fabric from the fabric holding means is thus done away with.

The formation of the stitches by this machine is as follows :-lVhen the needle 3 has pierced through the two cloth edges, there is formed on the upward motion thereof a loop of the upper thread below the cloth, into which loop the threaded looper 13 then enters as at Fig. 4. This loop remains below the cloth while theneedle continues to ascend, and the threaded looper advances as shown at Fig. 5, the nose l3? preventing the loop from sliding off the threaded looper. Before the needle again descends and the threaded looper -moves back again, the

as at Fig. 6, seizes the lower thread, and

spreads it out so that at the next stitch the under-thread passes around the needle. \Vhen the needle again passes below thefabric as at F 7 the first-named loop of the upper thread slides off the point of the threaded looper, so that on the upward motion of the needle, afresh loop is formed into which the threaded looper enters and thus the stitch formation is repeated. The peculiarity of the stitch formation therefore consists in that the loop of the upper thread always remains underneath the cloth, so that no clothpresser is necessary, whereby the above-men- V tioned advantages are obtained.

The thread clamp 18 holds the upper thread during the first part of the upward motion of needle 3, so that the loop forma tion is not merely dependent upon the friction of the upper. thread inv the cloth, which friction would only'be very small in the meshes of knitted goods and would not be suflicient for insuring the proper'formation of the loop, particularly when working at great speed.

WVith knitted goods the material is so place'dthat the stitching is effected in the direction of its width, so that the needle can enter the meshes-at the edge of the fabric.

The :mechanism herein shown and described for moving the sewing frame is substantially the same as that diselosedin NeveuxsPatent 786,833, of April 11,1905, and

shown in said patent.

Now what I claim and desire to secure by Letters Patent is the following:

1. In a two-thread over-edge sewing machine, the combination of a toothed plate for holding the fabric, and a frame movable along the fabric, with sewing mechanism carried by said frame and comprising a needle arranged to form a thread loop, a threaded looper of circular curvature mounted to swing about an axis eccentric to its outlinevso as not to stretch the needle loop and provided with a nose adjacent to its pivot, and a spreader.

2. In a two-thread over-edge sewing machine, the combination of means for bold ing the fabric, and a frame movable along the fabric, with sewing mechanism carried by said frame and comprising a needle, a threaded looper of circular curvature mounted to swing about a horizontal axis transverse to the direction of travel of said frame and provided with a loop-retaining nose adjacent to its pivot, anda spreader mounted to oscillate about a vertical axis.

3. In a sewing machine the combination of a vertically reciprocating needle arranged to pierce the cloth and form a thread loop, an oscillating threaded looper of symmetrical circular curvature arranged to pass alternately above and below the cloth and provided with a loop-retaining nose adjacent to its pivot and a spreader which remains permanently above the cloth.

4. In a sewing machine the combination of a vertically reciprocating needle arranged to form a thread loop, a threaded looper of symmetrical circular curvature mounted to oscillate about an axis transverse to the direction in which the sewing progresses and provided with a loop retaining nose adjacent to its pivot and a movable spreader which remains permanently above the cloth.

5. In a sewing machine the combination of a reciprocating needle arranged to form a thread loop, a symmetrically curved threaded looper arranged'to oscillate adjacent to the needle and to pass above and below the cloth, said looper being provided with a loop-retaining nose adjacent to its pivot and a spreader to move above the cloth.

6. The combination in a sewing machine of a stationary frame having means for holding the work and a movable frame arranged to travel lengthwise of the workholder, a needle, a symmetrically =curved threaded looper and a spreader carried by said movable frame, the needle being ar ranged to reciprocate up and down, the threaded looper to oscillate about an axis transverse to the direction of travel of said frame and being provided adjacent to its pivot with a loop-retaining nose and the spreader being arranged to oscillate above the cloth.

7 The combination, in a sewing machine, of a stationary frame having means for holding the work, and a movable frame arranged to travel lengthwise of the work holder, a needle, a threaded looper, and a spreader carried by said movable frame, the needle being arranged to reciprocate up and down through the fabric, the threaded looper to oscillate about an axis transverse to the direction of the frames travel, and the spreader being arranged to oscillate above the cloth about a vertical axis.

In testimony, that I claim the foregoing as my invention I have signed my name in presence of two witnesses, this seventh day of December 1904.

GEORG NIEDERMAYR.

Witnesses EVA SATTLER, CARL VVERKE. 

